Sources tell the Post that Hulu plans to transition to an authentication model, meaning access to content will be predicated upon some sort of subscription. Those same sources point to the shift as the reason for Providence Equity Partners unloading its stake for $200 million.

What's not entirely clear is just what this shift applies to. The Post's wording suggests it's all of Hulu, but the changes could well apply merely to the premium service Hulu Plus. We've reached out to Hulu for a comment and will update when we learn more.

Digital rights advocate Public Knowledge immediately released a statement from its president and CEO Gigi B. Sohn condemning the move:

Restricting access to legal content will only drive consumers to find illegal content. In particular, we are concerned about restricting access to TV programming available over free over-the-air broadcasting. It should be available online, regardless whether anyone subscribes to cable or satellite TV. By putting more restrictions on consumer access to popular content, the entertainment industry only removes any justification for stronger "anti-piracy" laws it is perpetually seeking from Congress.

All other considerations aside, the move is far from a risk-free. Hulu made $420 million in overall ad revenue last year, with CEO Jason Kilar predicting that Hulu Plus will account for more than half of revenue by late 2012. In March alone, the site boasted 31 million unique users. There’s little chance requiring a cable subscription won’t affect those numbers somehow.

That faint popping noise was likely the Aereo team celebrating with champagne.